--- a/pppd/magic.h	2019-12-31 02:31:26.000000000 +0100
+++ b/pppd/magic.h	2020-02-06 20:52:49.263657502 +0100
@@ -42,6 +42,8 @@
  * $Id: magic.h,v 1.5 2003/06/11 23:56:26 paulus Exp $
  */
 
+#include <sys/cdefs.h>
+
 void magic_init (void);	/* Initialize the magic number generator */
 u_int32_t magic (void);	/* Returns the next magic number */
 
